Hyperthyroidism in cats

Dr Sandra Karlsen
Lead Veterinarian
February 17, 2024

Cats with hyperthyroidism usually develop it due to benign tumours in their thyroid glands, which causes an excessive production of thyroid hormones. This condition is most commonly seen in cats around the age of 13. The thyroid glands, located in the neck, have a vital role in regulating the body's metabolic rate, and when affected by tumours, they disrupt this balance.

While the tumours are typically benign, they can lead to serious complications in the cat's organs. This highlights the need for timely veterinary intervention to diagnose and manage the condition. Regular check-ups with a veterinarian are crucial for early detection and treatment of hyperthyroidism in cats. These appointments allow for the identification of potential enlargement of the thyroid gland and prompt further evaluation.

What are common Hyperthyroidism signs in cats?

Early signs include

  • Weight loss despite increased appetite
  • Unkempt appearance and poor body condition
  • Gastrointestinal issues such as vomiting and diarrhoea
  • Increased thirst and urination
  • Respiratory symptoms including rapid breathing and difficulty breathing
  • Hyperactivity/restlessness and aggression

Intermediate to advanced signs include: 

  • Enlarged thyroid gland, which feels like a lump on the neck
  • Heart abnormalities such as murmurs, rapid heart rate, and an abnormal heartbeat known as a "gallop rhythm"

How is Hyperthyroidism managed in cats?  

When it comes to treating hyperthyroidism in cats, there are several options available. You can choose to use medication such as topical or Felimazole to help manage the symptoms, although it may have some side effects. Another option is radioactive iodine therapy, a highly effective treatment that may require several days in a specialised hospital. Surgery is also an option, as it offers a cure, but it does come with some risks. Adjusting your cat's diet can also be beneficial. Your veterinarian can provide guidance on which option is best suited for your cat's health needs.

Weight loss could be a sign of hyperthyroidism in cats.

What is the prognosis for cats with Hyperthyroidism?

Treating hyperthyroidism in cats usually leads to excellent results, even for older cats, ensuring a healthy life. Whether it's through radioactive iodine therapy, medication, or specialised diets, cats often return to normal within a few weeks, as long as the treatment is consistently administered and regular checkups are conducted.

Although there may be concerns about radiation therapy or surgery for older cats, it's important to remember that age itself is not a disease. In general, treatments for hyperthyroidism offer a high probability of restoring cats to good health, especially with consistent management and follow-up care.

Management tips for cats with Hyperthyroidism

At-home needs include:

  • Administer medication regularly with food and use pill pockets or alternate methods if needed.
  • Provide prescribed low-iodine food and ensure access to fresh water.
  • Create a stress-free environment with comfortable resting areas.
  • Monitor weight, appetite, and behaviour closely and schedule regular vet check-ups.

For end-of-life care:

In a crisis:

Immediately contact your vet if your cat exhibits symptoms such as weight loss, increased appetite, excessive thirst, or hyperactivity, as these could indicate hyperthyroidism, a condition that requires prompt diagnosis and treatment for your cat's well-being.

It is vital to begin end-of-life care discussions before your cat’s condition becomes unmanageable, or they begin losing their quality of life. 

Don’t wait until the very end. It’s important to consider your pet’s end-of-life journey early, so that you, your family and your pet are all supported through the process.

When the time comes, we’re here for you. Goodbye Good Boy provides a range of end-of-life services to make the difficult process of saying goodbye a little easier. 

We offer quality of life assessments from qualified vets, specialist grief counselling, at home euthanasia from dedicated end of life veterinarians, as well as cremation services and memorial options to help remember your pet for their unique character.

We are with you at every step of the journey.

To find out more, you can call our team of passionate pet lovers on 1800 953 619.